We are seeing some odd behaviour when going to the UI settings page (with the dark theme selected) and then somewhere else. The dark theme is lost/forgotten when the next page is displayed.

Click to view UI settings

Note: Dark theme is selected (the page was saved long time ago).

Click to a different page, i.e. System status

Default theme is used.

Reload page via F5. Dark theme is used.

Once the page is reloaded, if we navigate to any other page, including UI settings, the dark theme is used. Note if you navigate back to UI settings and then somewhere else, the dark theme is lost/forgotten again.